Ks0108 128x64 Glcd

[HenrikOlsson]

Hi guys,
A couple of weeks ago I recieved my EasyPIC4 board with various add-ons. Yesterday evening I thought I'd try to get the 128X64 GLCD working and I did - at least somewhat..... I can clear display as well as fill it completely and it looks good. However, as soon as I "draw" anyhing else on it the "intensity" seems to vary depending on how many pixels is "ON". The strange thing is that it looks OK when ALL pixels are on.

Here's a pic of what it looks like:



In the upper left corner the screen is cleared (filled with zeros), in the upper right corner it is filled with ones - good contrast and good intensity. Now, in the lower left corner the first 32 colums of page 0 is filled with the pattern %10101010, when this is done the intensity of each pixel is much lower compared to when all pixels are "on". And in the lower right corner of the photo I've "drawn" som horizontal lines across the screen, the intensity now is even lower.

So the question is: Has anybody seen this behavior on GLCD before? Am I doing something wrong? (Probably) Or is it just a low quality or even defective display?

Thanks!
/Henrik Olsson.

[Acetronics2]

Hi, Enrik

I used such a GLCD ( but classical green back colour : GDM12864A) driven by a 16F876, as a terminal with simple serial commands like P(oint) X,Y , L(ine) X1,Y1,X2,Y2, ...etc.
Also directly drivable from PC ... with a little program.

It is an "Electronique Pratique" magazine project, issue 279 p 86 ... no more downloadable ... halas !!!

... no problems, except for backlight that needed more than 5v !!!


Do you have 'external' sample programs to test it ???

But note its quite normal 1 point in the middle of the blank screen seems brightless than 1 in a group of 100 ... ( optics laws ! )

Alain

[T.Jackson]

I'm guessing defective. Unless there's some sort of software controllable contrast options (which I'm in high doubts about)

[mister_e]

i also have this board, i could send you a working .HEX to do some test. But first, check on the CD that came with. It may have some ready to go .HEX.

Also, make sure you have set JP12 to GRAPH position.

You could still send me your program, so i can check with mine.

I doubt your LCD is defective... there's some timing / routines to tweak.... let's say like old TV decades ago, when the image was just roll-over again and again.

let's say something like
http://www.fotosearch.com/CRT823/002381cf/
http://www.bbcmotiongallery.com/Cust...5-e1509bfc3722

[HenrikOlsson]

Thanks guys,
I loaded a HEX that came with the board. Turns out the contrast setting is really picky - it needs to be just right. Now it looks a little better but not much.

It's clearly visible, even when masking everything but the lowest line, that the "intensity" is changing when switching between "full screen on" and "a few horizontal lines". There's probably not anything wrong with it, I guess it's just a matter of you get what you pay for.

Thanks again!
/Henrik Olsson.

[mister_e]

yeah, their contrast should be better. BUT i never tried and look for the right datasheet... sure we could discover something interesting in... they shipped me a LGM12864B-NSW-BBS proudly made in China.

Here's the snail speed link for the datasheet... be patient and you should have it before christmas.
http://www.xmocular.com/pdf/GDM12864B.pdf

[Acetronics2]

Some more data here:

http://www.selectronic.fr/includes_s...LCD/8690-2.pdf

Alain

[mister_e]

their contrast line schematic is bad... but knowing you can sit a GLCD or character LCD in the same header... they had to do some kind of compromise.

[mister_e]

Some more data here:

http://www.selectronic.fr/includes_s...LCD/8690-2.pdf

Alain

It's faster that mine... but unfortunatly, the pin-out is not the same as the B version which fit the board SlikScreen as well...

[Acetronics2]

MORE data : http://www.lextronic.fr/ODT/S6B0108.pdf

and http://www.lextronic.fr/ODT/S6B0107.pdf

... good luck !!!

[Marchy]

Hello overybody,

I purchased a GDM12864B but I do nt succeed in making it display anything. All the information I have are from Xiamen cular (pdf) but I do not understand part of it. After many tries, none of my code work. I guess my LCD module is out of order. could one of you send me part of his code, just to see if my lcd module is still alive or not. I just want to initialise it and display a single dot or byte to see if it still works.

Thanks a lot

Marchy